Okay, I'm in giggling fits. This is like something out of Nick Park's animation. This SO could have been straight out of Chicken Run (eerily, either Ginger OR one of those evil chicken profiteering companies could have been the architects...).
Now they need a coop that looks like a 3-compartment cedar compost bin (for folks that are too hippy or eco-cool to have a ginormous trash can without making the neighbors suspicious).
Seriously, if your need for stealth is THAT great, why not put a dog kennel in the yard with a dog house, privacy lathe in the chain links, and a big BEWARE OF DOG sign on the gate? If you want to go whole hog (or dog), get a tape recording of a dog barking and play it when the neighbors start to get nosy.